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G&S Tire Grinder

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  • G&S Tire Grinder

    G&S Tire Grinder
    A new kind of tire truing machine, suitable for most kinds of 1/32 and 1/24 wheels and axles.

    First, the name. G is for Gaub, or Greg, whichever you prefer. S is for Samson, as in Dennis Samson. His original design for a rotating sanding drum machine for whole axles (e.g. pressed on wheels) inspired this design to a great extent. It was with his input and feedback, along with others in the community, that this machine was finally realized as shown. I also owe thanks to Giacomo Verlini, aka JamieG from Sweden, for his design for the sanding sleeve drums that I have used for this machine. You can find his Tyre Truer MKIII for slot cars 1/32 and many other great models on his Thingiverse page.

    This machine is intended to be a "good enough" machine to get casual racers started with their tire truing needs. It is not intended to replace or compete with precision milled machines for high level competitions. As it's designed to facilitate tire truing on a variety of 1/32 and 1/24 size tires on pressed-on plastic wheels, it's not meant for racers who are using precision metal wheels, though it can also be used for those kinds of wheels/tires. Someone who has no cars with pressed on wheels should probably look elsewhere for a more precise machine, if they don't already have one.

    This machine will be provided free to download, print, and build your own. The license is Creative Commons, Attribution, Non-Commercial, Share-Alike. From a practical standpoint, that just means no one else is allowed to market or sell the files, plans, prints, or completed machines without my express permission. Credit to my project must be given any time the machine is shown or shared. Since I'm releasing it as open source, the "Share-Alike" part of the license means that if you design a machine that is derived from this design, you must also share it as open source with the appropriate credit to me. If you are contacted by someone to print the parts as a printing service, you have my permission to do so, but you cannot advertise that you are printing the parts for sale. I reserve the right to market and sell prints and/or machines until I am no longer able to do so. Pricing for prints/kits/machines TBD.

    All of the parts are designed to be printed on any FFF (filament) 3d printer with no need for supports. PLA can be used, and is preferred, for the majority of parts due to its rigidity. Parts that are subject to heat, such as the pulleys and sanding drums, should be printed in PETG, or similar high temperature material. The largest piece, the base plate, measures 168x120mm, and so should be able to be printed on most machines, even many of the "mini" printers.

    • 15x - M3x10mm Socket Head Cap Screws
    • 12x - M3x6mm Socket Head Cap Screws
    • 2x - M3x6mm countersunk screws
    • 2x - M3x4mm set screws
    • 15x - M3 Square Nuts
    • 1x - 1/4-20 x 4.5" Hex Head Bolt, fully threaded
    • 2x - 1/4-20 x 2" Hex Head Bolt, fully threaded
    • 3x - 1/4-20 x 7/32" Hex Nuts
    • 1x - 1/4-20 Nylon Lock Nut
    • 1x - 1/4-20 Acorn Hex Nut
    • 1x - 1/4x3/8x1/2" steel spacer
    • 1x - RS550 DC motor
    • 1x - 1x7 20x53x13mm Conical Spring
    • 4x - R188 bearings
    • 3x - 1-1/2" ID, 1-11/16" OD, 3/32" Width O-Rings
    • 2x - 1"x1" spiral band sanding sleeves, 80 grit

    Printing instructions:

    Most parts can be printed in PLA, but there should be at least 4 perimeters (1.6mm thickness) and most parts should have a strong and dense infill, such as 30% Cubic.

    The round/pulley parts should be printed in PETG or other high temp material, with a random seam position to reduce a “lump” from an aligned seam.

    The small pulley for the motor, and the split pulley for the slot car axle should be printed 100% infill because they need set screws to stay in place and will split easily if not solid.

    Review the photos and STEP file to confirm assembly.

    Assembly guide and/or video will be forthcoming.

  • #2
    Key Features of the G&S Tire Grinder
    - One motor turns all axles
    - Only two screws to remove/replace the entire grinding assembly for different grits
    - Screws beneath the ball bearings to adjust parallel
    - Spring loaded axle carrier to allow "grind and release" truing methods with ease
    - Indicator knob for precise repetition of tire diameters as needed
    - Consistent tension of o-rings due to double-pulley design
    - O-rings can easily be moved side to side to accommodate various axle configurations
    - standard 1/32 bushings snap into axle carrier, but V-shape still allows smaller or larger bushings or bearings to stay in place
    - Distance between sanding drums accommodates most 1/24 and 1/32 wheels/axles
    - sanding surface cannot contact axle pulley/o-ring


    • #3
      Assembly Video